[ovirt-users] Storage questions

Fernando Frediani fernando.frediani at upx.com.br
Thu Nov 24 13:33:36 UTC 2016


As many may think contributions don't resume only to writing lines of 
code certainly. Thanks for the invitation. I'm sure it can be an 
interesting exercise.


On 24/11/2016 11:26, Yaniv Kaul wrote:
>
>
> On Thu, Nov 24, 2016 at 1:39 PM, Fernando Frediani 
> <fernando.frediani at upx.com.br <mailto:fernando.frediani at upx.com.br>> 
> wrote:
>
>     I have the similar frustrations with oVirt Oscar, specially
>     regarding ways to managed local and shared storage.
>
>     Instead of making it easier for the many scenarios used by people
>     seems the design process seems was a bit dificulted. Just look to
>     one of market leaders, VMware vSphere and one can easily see the
>     flexibility it has to move things around, even if they don't
>     belong to the same cluster. As we are talking about Linux 'under
>     the hood' it shouldn't need much in order to do similar things.
>
>     Perhaps people who work in the design can flexibilize a bit some
>     of these things.
>
>
> I'd like to use the opportunity and encourage the community to send 
> patches. Both to the design as well as the implementation.
> The value of open source is not only in consumption, but also in 
> participation.
> Active contribution is not only the best way to influence the project, 
> but it is also a rewarding and joyful experience to the contributor.
> Getting into the internal bits of a project, understanding why some 
> key design decisions were made, suggesting and implementing 
> enhancements and changes isn't easy.
> It is a journey, with ups and downs, but certainly a great ride.
>
> Feel free to reach the developers at the devel mailing list and we'll 
> be happy to assist in onboarding, consulting, advice and reviews for 
> your code.
> Y.
>
>
>     On 23/11/2016 10:03, Oscar Segarra wrote:
>>     Hi Pave, users,
>>
>>     Thanks a lot for your clarifications:
>>
>>     I'm surprised because this system is very rigid... I don't
>>     understand why oVirt has been designed with this limitations.
>>
>>     Regarding to my performance worry (without configuing any kind of
>>     backup):
>>
>>     Do you mean that 1000 vdis against a shared gluster volume
>>     provided by 10 physical hosts (the same hosts that run kvm) won't
>>     have performance problems? Do you know any similar experience?
>>
>>     And related to rsync, as Gluster Geocluster is fully supported,
>>     do you have experience backing up VMs using this product?
>>
>>     Thanks a lot.
>>
>>
>>     2016-11-23 12:36 GMT+01:00 Pavel Gashev <Pax at acronis.com
>>     <mailto:Pax at acronis.com>>:
>>
>>         1. You can create a datacenter per host, but you can't have a
>>         storage shared among datacenters.
>>
>>         2. I mean backups would add performance problems. When you
>>         rsync a disk image, in order to find the difference it reads
>>         both the source and the destination images. In other words,
>>         if you want to make daily backups, rsync will daily read
>>         everything located on local storages, plus everything located
>>         on gluster. Plus, in order to make consistent backups, you
>>         have to make VM snapshots and merge them after rsync.
>>
>>         *From: *Oscar Segarra <oscar.segarra at gmail.com
>>         <mailto:oscar.segarra at gmail.com>>
>>         *Date: *Wednesday 23 November 2016 at 13:42
>>         *To: *Pavel Gashev <Pax at acronis.com <mailto:Pax at acronis.com>>
>>
>>
>>         *Cc: *users <users at ovirt.org <mailto:users at ovirt.org>>
>>         *Subject: *Re: [ovirt-users] Storage questions
>>
>>         Hi Pavel,
>>
>>         1. Local storage datacenter doesn’t support multiple hosts.
>>         If you have multiple hosts, you have to have a shared
>>         storage, even it’s a hyper-converged setup.
>>
>>         Is it not possible to create a datacenter for each node and
>>         set up a shared storage (transversal to all hosts) for
>>         storing engine and other infraestructure virtual servers?
>>
>>         2. In your case most of disk and network performance would be
>>         used by backups. And a backup cycle would take more than 24
>>         hours. Even rsync would take much resources since it has to
>>         at least read the whole disk images.
>>
>>         Do you mean that 1000 vdis against a shared gluster volume
>>         provided by 10 physical hosts (the same hosts that run kvm)
>>         won't have performance problems? Do you know any similar
>>         experience?
>>
>>         Related to rsync, the idea is launch one rsync process per
>>         physical node for backing up the contained virtual machines.
>>         But if you expect rsync to require the whole day... do you
>>         mean gluster georeplication will require 24 hours too?
>>
>>         Thanks a lot
>>
>>         2016-11-23 11:02 GMT+01:00 Pavel Gashev <Pax at acronis.com
>>         <mailto:Pax at acronis.com>>:
>>
>>             Oscar,
>>
>>             I’d make two notes:
>>
>>             1. Local storage datacenter doesn’t support multiple
>>             hosts. If you have multiple hosts, you have to have a
>>             shared storage, even it’s a hyper-converged setup.
>>
>>             2. In your case most of disk and network performance
>>             would be used by backups. And a backup cycle would take
>>             more than 24 hours. Even rsync would take much resources
>>             since it has to at least read the whole disk images.
>>
>>             I’d recommend a scenario with a dedicated shared storage
>>             that supports snapshots.
>>
>>             *From: *<users-bounces at ovirt.org
>>             <mailto:users-bounces at ovirt.org>> on behalf of Oscar
>>             Segarra <oscar.segarra at gmail.com
>>             <mailto:oscar.segarra at gmail.com>>
>>             *Date: *Wednesday 23 November 2016 at 03:11
>>             *To: *Yaniv Dary <ydary at redhat.com <mailto:ydary at redhat.com>>
>>             *Cc: *users <users at ovirt.org <mailto:users at ovirt.org>>
>>             *Subject: *Re: [ovirt-users] Storage questions
>>
>>             Hi,
>>
>>             As on oVirt is it possible to attach local storage I
>>             supose it can be used to run virtual machines:
>>
>>             I have drawn a couple of diagrams in order to know if is
>>             it possible to set up this configuration:
>>
>>             1.- In on-going scenario:
>>
>>             Every host runs 100 vdi virtual machines whose disks are
>>             placed on local storage. There is a common gluster volume
>>             shared between all nodes.
>>
>>             ágenes integradas 1
>>
>>             2.- If one node fails:
>>
>>             ágenes integradas 2
>>
>>             oVirt has to be able to inventory the copy of machines
>>             (in our example vdi201 ... vdi300) and start them on
>>             remaining nodes.
>>
>>             ¿Is it possible to reach this configuration with oVirt?
>>             ¿or something similar?
>>
>>             Making backup with the import-export procedure based on
>>             snapshot can take lot of time and resources. Incremental
>>             rsync is cheaper in terms of resources.
>>
>>             Thanks lot.
>>
>>             2016-11-22 10:49 GMT+01:00 Yaniv Dary <ydary at redhat.com
>>             <mailto:ydary at redhat.com>>:
>>
>>                 I suggest you setup that environment and test for the
>>                 performance and report if you have issues.
>>
>>                 Please note that currently there is no data locality
>>                 guarantee, so a VM might be running on a host that
>>                 doesn't have its disks.
>>
>>                 We have APIs to do backup\restore and that is the
>>                 only supported option for backup:
>>
>>                 https://www.ovirt.org/develop/release-management/features/storage/backup-restore-api-integration/
>>                 <https://www.ovirt.org/develop/release-management/features/storage/backup-restore-api-integration/>
>>
>>                 You can look at the Gluster DR option that was posted
>>                 a while back, you can look that up.
>>
>>                 It used geo replication and import storage domain to
>>                 do the DR.
>>
>>
>>                 Yaniv Dary
>>
>>                 Technical Product Manager
>>
>>                 Red Hat Israel Ltd.
>>
>>                 34 Jerusalem Road
>>
>>                 Building A, 4th floor
>>
>>                 Ra'anana, Israel 4350109
>>
>>                 Tel : +972 (9) 7692306 <tel:%2B972%20%289%29%207692306>
>>
>>                         8272306
>>
>>                 Email: ydary at redhat.com <mailto:ydary at redhat.com>
>>
>>                 IRC : ydary
>>
>>                 On Mon, Nov 21, 2016 at 5:17 PM, Oscar Segarra
>>                 <oscar.segarra at gmail.com
>>                 <mailto:oscar.segarra at gmail.com>> wrote:
>>
>>                     Hi,
>>
>>                     I'm planning to deploy a scalable VDI
>>                     infraestructure where each phisical host can run
>>                     over 100 VDIs and I'd like to deploy 10 physical
>>                     hosts (1000 VDIs).
>>
>>                     In order to avoid performance problems
>>                     (replicating 1000VDIs changes over gluster
>>                     network I think can provoque performance
>>                     problems) I have thought to use local storage for
>>                     VDI assuming that VDIs cannot be migrated between
>>                     phisical hosts.
>>
>>                     ¿Is my worry founded in terms of performance?
>>
>>                     ¿Is it possible to utilize local SSD storage for
>>                     VDIs?
>>
>>                     I'd like to configure a gluster volume for backup
>>                     on rotational disks (tiered+replica 2+ stripe=2)
>>                     just to provide HA if a physical host fails.
>>
>>                     ¿Is it possible to use rsync for backing up VDIs?
>>
>>                     If not ¿How can I sync/backup  the VDIs running
>>                     on local storage on the gluster shared storage?
>>
>>                     If a physical host fails ¿How can I start the
>>                     latest backup of the VDI on the shared gluster?
>>
>>                     Thanks a lot
>>
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>>                     <http://lists.ovirt.org/mailman/listinfo/users>
>>
>>
>>
>>
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